Convert an RFC 3339 time to a standard Python timestamp

Viewed 46418

Is there an easy way to convert an RFC 3339 time into a regular Python timestamp?

I've got a script which is reading an ATOM feed and I'd like to be able to compare the timestamp of an item in the ATOM feed to the modification time of a file.

I notice from the ATOM spec, that ATOM dates include a time zone offset (Z<a number>) but, in my case, there's nothing after the Z so I guess we can assume GMT.

I suppose I could parse the time with a regex of some sort but I was hoping Python had a built-in way of doing it that I just haven't been able to find.

15 Answers

You don't include an example, but if you don't have a Z-offset or timezone, and assuming you don't want durations but just the basic time, then maybe this will suit you:

import datetime as dt
>>> dt.datetime.strptime('1985-04-12T23:20:50.52', '%Y-%m-%dT%H:%M:%S.%f')
datetime.datetime(1985, 4, 12, 23, 20, 50, 520000)

The strptime() function was added to the datetime module in Python 2.5 so some people don't yet know it's there.

Edit: The time.strptime() function has existed for a while though, and works about the same to give you a struct_time value:

>>> ts = time.strptime('1985-04-12T23:20:50.52', '%Y-%m-%dT%H:%M:%S.%f')
>>> ts
time.struct_time(tm_year=1985, tm_mon=4, tm_mday=12, tm_hour=23, tm_min=20, tm_sec=50, tm_wday=4, tm_yday=102, tm_isdst=-1)
>>> time.mktime(ts)
482210450.0

No builtin, afaik.

feed.date.rfc3339 This is a Python library module with functions for converting timestamp strings in RFC 3339 format to Python time float values, and vice versa. RFC 3339 is the timestamp format used by the Atom feed syndication format.

It is BSD-licensed.

http://home.blarg.net/~steveha/pyfeed.html

(Edited so it's clear I didn't write it. :-)

The new datetime.fromisoformat(date_string) method which was added in Python 3.7 will parse most RFC 3339 timestamps, including those with time zone offsets. It's not a full implementation, so be sure to test your use case.

>>> from datetime import datetime
>>> datetime.fromisoformat('2011-11-04')
datetime.datetime(2011, 11, 4, 0, 0)
>>> datetime.fromisoformat('2011-11-04T00:05:23')
datetime.datetime(2011, 11, 4, 0, 5, 23)
>>> datetime.fromisoformat('2011-11-04 00:05:23.283')
datetime.datetime(2011, 11, 4, 0, 5, 23, 283000)
>>> datetime.fromisoformat('2011-11-04 00:05:23.283+00:00')
datetime.datetime(2011, 11, 4, 0, 5, 23, 283000, tzinfo=datetime.timezone.utc)
>>> datetime.fromisoformat('2011-11-04T00:05:23+04:00')   
datetime.datetime(2011, 11, 4, 0, 5, 23,
    tzinfo=datetime.timezone(datetime.timedelta(seconds=14400)))

The simplest solution for me has been dateutil python standart library.

from dateutil.parser import parse

dt = "2020-11-23T11:08:23.022277705Z"
print(parse(dt))

Output:

2020-11-23 11:08:23.022277+00:00

If you don't need the timezone element, just simply set timezone info to None

print(parse(t).replace(tzinfo=None))

The output is a nice and clean datetime object:

2020-11-23 11:08:23.022277

feedparser.py provides robust/extensible way to parse various date formats that may be encountered in real-world atom/rss feeds:

>>> from feedparser import _parse_date as parse_date
>>> parse_date('1985-04-12T23:20:50.52Z')
time.struct_time(tm_year=1985, tm_mon=4, tm_mday=12, tm_hour=23, tm_min=20,
                 tm_sec=50, tm_wday=4, tm_yday=102, tm_isdst=1)

You could use a Google API Core package. They have a really straightforward Datetime to RFC 3339 conversion function. You can find more info in their docs.

Its usage is as simple as:

from google.api_core.datetime_helpers import to_rfc3339

rfc3339_str = to_rfc3339(datetime.now())

They even have a function that works the other way around from_rfc3339 and from_rfc3339_nanos.

I have been doing a deep dive in dateimes and RFC3339 and recently come across the arrow library and have just used and solved my problem:

import arrow

date_string = "2015-11-24 00:00:00+00:00"
my_datetime = arrow.get(date_string).datetime
Related